Improving pre-harvest sprouting resistance in rice by editing OsABA8ox using CRISPR/Cas9

Abstract Pre-harvest sprouting (PHS) in cereal crops, is a universal phenomenon that affects grain yield and quality (Tai et al. 2021). Breeders use different methods to strengthen seed dormancy to prevent PHS including genome editing. Abscisic acid is one of the phytohormones that promote seed dormancy. ABA8ox genes encode abscisic acid 8’ hydroxylase (ABA8OX) which determines the level of ABA content by catabolizing ABA (Vallabhaneni and Wurtzel 2010). Three genes in rice encode ABA8’ hydroxylases, namely OsABA8ox1 ( LOC_Os02g47470 ), OsABA8ox2 ( LOC_Os08g36860 ) and OsABA8ox3 ( LOC_Os09g28390 ) (Kushiro et al. 2004; Cai et al. 2015; Zhang et al. 2020). Each gene is expressed in different tissues of rice.